The Animal Facility Core will meet the needs of the Program Project Grant members for creating[unreadable] new mouse strains and for established, shared strains. To improve efficiencies the Core will provide and[unreadable] maintain genetically complex animals that are used by multiple projects, assist with backcrosses, and also[unreadable] assist with mice used in genetic mapping projects. There are four SPECIFIC AIMS for this Core.[unreadable] 1. To breed and genetically characterize unique and non-routine mouse strains for use by all the program[unreadable] project members. This service will ensure that animals are readily available for use in experiments for all of[unreadable] the PPG members.[unreadable] 2. To assist program project members with routine backcrossing of newly obtained or derived strains to the[unreadable] appropriate genetic backgrounds for planned studies. Fixed genetic backgrounds will be essential for many[unreadable] of the studies in the PPG.[unreadable] 3. To provide breeding and collection services for genetic mapping projects that are being performed in two[unreadable] of the projects in the PPG (projects 3 and 4). The Core will help with the maintenance and generation of[unreadable] animals in these crosses, as well as collection of DNA for genotyping.[unreadable] 4. To ensure animals provided to program project members are healthy and maintained in a pathogen-free[unreadable] environment for the proposed studies.[unreadable] The availability of the mouse Core will ensure that multiple investigators in the PPG will have sufficient[unreadable] animals available for their studies in a timely and efficient manner.